Coupling batteries in parallel is a common method of providing more power to a load. For example, some known portable blood glucose meters require two batteries coupled in parallel to power the meter's load (e.g., electronics). Accidental reverse battery installation in such devices can cause one or more problems including abnormal device operation, damage to the device's load, and/or premature battery discharge. Some devices employ mechanical safeguards, such as, e.g., special battery connectors, to prevent inadvertent reverse battery installation. However, mechanical safeguards can be expensive and/or may not be effective with certain kinds of batteries, such as, e.g., coin or lithium cell type batteries. Some devices employ circuitry to protect against reverse battery installation. However, some known protection circuits, such as those using diodes, can result in undesirable power losses. Other known protection circuits, such as those using MOSFETs (metal-oxide-semiconductor-field-effect-transistors), may not be effective in devices powered by parallel-coupled batteries. In particular, the type of batteries and/or the type of parallel-battery holders and/or connectors used in a device can render some known MOSFET protection circuits ineffective. Thus, a need still exists to provide reverse battery protection for devices powered by batteries coupled in parallel.